However, are you worried about long-term consequences? While one part of going beyond 15-20% is potential problems with soft tissue resisting to stretching, another part is the life-long feasibility of the new leg arrangement. What are your thoughts about the possibility of developing osteoarthritis in the long run? I'm just curious about your take because that's not a huge topic of discussion in the community.
Please allow me to address your question in two parts--first, potential problems with soft-tissue resisting stretching:
Foremost, soft-tissue presents more of a short-term rather than a long-term problem. By this I mean the damage usually gets done during distraction because a certain soft-tissue cannot stretch the same amount as that moment's distraction. As a result, something tears or ruptures or announces great pain, etc.
In contrast, once you stop distracting, soft-tissue has the rest of your life to catch up.
It is important to understand what happens when you distract. Nerves can grow up to 1 mm per day so folks who distract up to 1 mm generally need not worry about nerve damage. Muscle tissue, tendons, ligaments, blood vessels, and skin is another matter.
Muscle, tendons, and ligaments fight back against distraction. It is hard to hurt these tissues because they are very tough. Blood vessels and skin stretch. To me, a ruptured blood vessel poses the greatest risk; yet, skin at the pin sites seems to present the most common problem.
On my 35 day photo, you can see two wounds, one on each of my lower shins. These wounds were each pin sites. As I distracted past 6 cm, my skin refused to keep up at these pin sites. As a result, the skin started to open up below each pin--like an old-fashioned keyhole. This type of wound is common. I had to keep a very close eye on these wounds to ensure each remained within the realm of acceptable risk.
I wrote repeatedly that I believe you must listen to your body as you go through the process. Wounds such as mine are precisely the type of thing I am writing about--if they became only a little bit worse, I would have had to stop distraction before I reached my goal.
On your second point--osteoarthritis. I am aware of no connection between limb lengthening and osteoarthritis. Osteoarthritis is a condition of the
joints caused by a breakdown of cartilage in the joints. Limb-lengthening surgery does not directly involve any joint.
This is not to imply that increased height does not implicate some joints--of course it does. When you become 3 inches taller, your center-of-gravity changes. Likewise, the forces on your knee joint as a fulcrum change because the length of the levers acting upon the fulcrum (your femur and tibia) change in relation to one another.
This means that you have to create new muscle memory and become accustomed to your new leg length and center of balance. A perfect example is that a couple of nights ago I was laying on the sofa with my foot up on the sofa arm. I pulled my leg back so that my foot would drop onto the sofa cushion--except it didn't.
My mind understood that my foot should have dropped onto the sofa cushion because my mind was operating from memory of my old leg length. Now however, I still had 3.5 inches to go before my foot cleared the sofa arm.
In time, new muscle memory will replace the old and I will forget what it was to be my old height. Likewise, I will use my ankle, knee, and hip joints slightly differently but I don't think these is any reason to believe that I will wear them out any more than I would have before lengthening.